Rit (Vísindafélag Íslendinga) - 01.06.1967, Qupperneq 163

159
Iceland lies on the junction of the Mid-Atlantic Ridge and
the Scotland—Greenland Ridge, which have completely diffe-
rent structures. Scarcity of NW-SE trending structures in
Iceland indicates that the Scotland-Greenland Ridge may
have formed as a result of the splitting up of the rift of the
Mid-Atlantic Ridge into parallel short volcanic zones active
where the Scotland-Greenland Ridge crosses Iceland.
REFERENCES
Rödvarsson, G. & G. P. L. Walker, 1964: Crustal drift in Iceland. Geophys.
J. R. Astr. Soc. 8: 285—299.
Einarsson, Tr., 1959: The Pleistocene volcanism in the north of Skaga-
fjördur and the paleomagnetic dating of topography in middle north-
ern Iceland. Náttúrufrædingurinn 29: 113—133 (in Icelandic with
English summary).
— 1962: Upper Tertiary and Pleistocene rocks in Iceland. Soc. Sci. Isl.
Rit 36, 196 pp.
— 1965: Remarks on crustal structure in Iceland. Geophys. J. R. Astr.
Soc. 10, 283-288.
Saemundsson, K., 1967: Vulkanismus und Tektonik des Hengill-Gehietes.
Acta nat. Island. II, 7: 101 pp.
Vine, F. J., 1966: Spreading of the ocean floor. Science 154: 1405—1415.
Walker, G. P. L., 1965: Evidence of crustal drift from Icelandic geology.
Phil. Trans., Ser. A 258: 199—204.
DISCUSSION
Th. Sigurgeirsson: Since Trausti Einarsson published his
paleomagnetic maps of the Hvalfjördur and the Hreppar areas
in 1962, Grasty in Cambridge has made some K/Ar-age deter-
minations on basalts from this area. Two samples taken at
the boundary between RL and N2 in Kvígindisfell give an
age of 1,8 million years. A sample from the uppermost layer
in r2 at Háifoss gave 2,9 million years. A fourth sample taken
from the upper part of R2 in Thrándarstadafjall north of
Kjölur gave 3,2 million years. These results indicate that the
N2 group in the Hvalfjördur area and the N2 group in the